update docs

Author: SpacePossum

README.md

@@ -14,9 +14,12 @@ If you only need this library during development, for instance to run your proje
 
 ### Usage
 
+#### Generating diff
+
 The `Differ` class can be used to generate a textual representation of the difference between two strings:
 
 ```php
+<?php
 use SebastianBergmann\Diff\Differ;
 
 $differ = new Differ;
@@ -31,6 +34,76 @@ The code above yields the output below:
     -foo
     +bar
 
+There are three output builders available in this package:
+
+#### UnifiedDiffOutputBuilder 
+
+This is default builder, which generates the output close to udiff and is used by PHPUnit.
+
+```php
+<?php
+
+use SebastianBergmann\Diff\Differ;
+use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
+
+$builder = new UnifiedDiffOutputBuilder(
+    "--- Original\n+++ New\n", // custom header
+    false                      // do not add line numbers to the diff 
+);
+
+$differ = new Differ($builder);
+print $differ->diff('foo', 'bar');
+```
+
+#### StrictUnifiedDiffOutputBuilder
+
+Generates (strict) Unified diff's (unidiffs) with hunks,
+similar to `diff -u` and compatible with `patch` and `git apply`.
+
+```php
+<?php
+
+use SebastianBergmann\Diff\Differ;
+use SebastianBergmann\Diff\Output\StrictUnifiedDiffOutputBuilder;
+
+$builder = new StrictUnifiedDiffOutputBuilder([
+    'collapseRanges'      => true, // ranges of length one are rendered with the trailing `,1`
+    'commonLineThreshold' => 6,    // number of same lines before ending a new hunk and creating a new one (if needed)
+    'contextLines'        => 3,    // like `diff:  -u, -U NUM, --unified[=NUM]`, for patch/git apply compatibility best to keep at least @ 3
+    'fromFile'            => null,
+    'fromFileDate'        => null,
+    'toFile'              => null,
+    'toFileDate'          => null,
+]);
+
+$differ = new Differ($builder);
+print $differ->diff('foo', 'bar');
+```
+
+#### DiffOnlyOutputBuilder
+
+Output only the lines that differ.
+
+```php
+<?php
+
+use SebastianBergmann\Diff\Differ;
+use SebastianBergmann\Diff\Output\DiffOnlyOutputBuilder;
+
+$builder = new DiffOnlyOutputBuilder(
+    "--- Original\n+++ New\n"
+);
+
+$differ = new Differ($builder);
+print $differ->diff('foo', 'bar');
+```
+
+#### DiffOutputBuilderInterface
+
+You can pass any output builder to the `Differ` class as longs as it implements the `DiffOutputBuilderInterface`. 
+
+#### Parsing diff
+
 The `Parser` class can be used to parse a unified diff into an object graph:
 
 ```php
@@ -114,13 +187,8 @@ The code above yields the output below:
                                                 [type:SebastianBergmann\Diff\Line:private] => 3
                                                 [content:SebastianBergmann\Diff\Line:private] =>         $b = new Money(2, new Currency('EUR'));
                                             )
-
                                     )
-
                             )
-
                     )
-
             )
-
     )